James beechbe and teeeence p



(NQ Mudel.)

J'. BB'ECHER 81: T. P. SMART.

JAK.

Patnted Feb. 3, 1885.

N. PETERS, Puma-Llnmgraplwr. Washngmn, n. C.

Nrrn STATES Arniv'r Prina JAMES BEECHER AND TERRENCE P. SMART, OFPHILADELPHIA, PA.

JACK.

SPECIFICATION forming part of Letters Patent No. 311,716, dated February3, 21885.

Application tiled August 7, 1884. (No model.)

To @ZZ whom, it may concern,.-

Be it known that we, JitMns BEnclrnR and TERRENCRP. SMART, citizens ofthe United States, residing in Philadelphia, Pennsylvania, have inventedcertain lniprovements in Jacks, of which the following is aspecitlcation.

Our invention consists of a jack intended, principally, for bracing theplank linings of sewer-trenches and like excavations, the main object ofour invention being to protect the threaded portions of the jack frominjury and to prevent the clogging ofthe saine by the access thereto ofearth or other foreign matters.

In the accompanying drawings, Figure 1 is a perspective view of ourimproved jack; Fig. 2, a longitudinal section of the same with thethrust-rods in elevation; Fig. 3, a longitudt nal section ofthe centraltube; Fig. 4, a transverse section of the same on the line 1 2, Fig. 2;and Fig. 5, a side view of the thrust'rods detached from the tube.

The jack consists of a central'tnbe, A, and two thrust-rods, B B', eachof which is provided at the outer end with a claw-plate, a, and isthreaded at the inner end for adaptation to a nut in the tube A, the rodB and its nut b having alel't-hand thread, and the thread of the rod Band its nut b being right-handed, as shown, so that when the claw-platesare pressed against the planks on opposite sides ofthe trench, and therods thereby prevented from turning, the rotation of the tube in onedirection will cause the rods to be thrust outward, so as to brace theplanks, the rods being retracted on turning the tube in the oppositedirection. The outer ends, m, of the tube A litsnugly to the unthreadedportions ofthe rods B B, so as to prevent the access of dirt or otherforeign rnatter to the threads, and between said ends and the nuts b bthe tube is chambered internally, as shown at n n, so as to lessen itsweight and reduce the friction on the rods. The tube is also chalnberedatp p between the nuts b b', and the center of the tube is preferablyprovided with transverse openings d for the reception of a bar, wherebythe tube can be readily turned, the openings being incased, as shown, sothat no dirt can through them gain access to the threaded V portionsofthe tube or rods.

Instead of forming transverse openings in the tube, the latter may hav-eone or more shallow depressions for the reception of the pin of aSpanner; or it may be made square or hexagonal for the use of anordinary wrench, the openings, however, being preferred.

The tube A presents a straight surface, so that when used in the bottoniof the trench it will not interfere with the proper support of aplatform such as is ordinarily used in constructing sewers and likeunderground con duits. 1

We claim as our inventionl. The combination of the threaded thrustrods BB with the tube A, having internal nuts, b b', and ends m, which titsnugly to the un# threaded portions of the rods, as set forth.

2. The combination of the threaded thrustrods B B with the tube A,having internal nuts, b b', chambered portions n n, and. ends m m, whichlit snugly tothe unthreaded. portions of the rods, as specified.

3. The combination ofthe threaded rods B B with the tube A, havinginternal nuts, b b', and incased transverse openings d, as set forth.

In testimony whereof we have signed our naines to this specification inthe presence of two subscribing witnesses.

JAMES BEECHER. TERRENCE P. SMART. Witnesses:

HARRY SMITH, HENRY HowsoN, J r.

